Roller cutter



July s, 1941. Al c. CATLAND 2,248,339

ROLLER CUTTER Filed oct. 23, 1939 Patented7 July 8, 1941 ROLLER CUTTER Alfred C. Catland, Alhambra, Calif., assignor to Globe Oil Tools Company, Los Nietos, Calif., a corporation Yci California Application October 23, 1939, Serial No. 300,772

(Cl. Z55- 71) 2 Claims.

This invention relates to cutting elements and relates more particularly to roller cutters for use on rotary well drilling tools. A general object of this invention is to provide a readily iiushed and highly eicient roller cutter.

Another object of this invention is to provide a roller cutter in which the teeth are formed and related so that the circulation lluid has free access to the spaces between the teeth throughout substantially the entire length of the rows of teeth to prevent mud, cuttings, etc. from accumulating between the teeth. In the operation of rock bits in rotary well drilling it is essential that the cutters be kept free of accumulations of cuttings and mud. The circulation fluid is usually discharged under pressure from nozzles in the bit body to wash the mud and cuttings from the cutters. It has been a somewhat general practice to form or arrange the teeth of the cutters in helical rows. With the teeth arranged in helical rows it is diflicult, if not impossible, to arrange the discharge nozzles in such a manner that the jets of circulation iiuid have full access to the helical serrations throughout substantial parts of the rows of teeth. In the cutter of the present invention the teeth are not arranged in helical series but are positioned in such a manner that the jets of circulation iiuid have substantially free access to the serrations between them to assure the complete flushing of the several teeth.

Another object of this invention is to provide a roller bit in which the cutting teeth are formed and related so that they cannot track in their engagement with the earth formation at the bottom of the well. In the improved cutter of the present invention the teeth are arranged in longitudinal rows and in circumferentially extending sets of these. rows and the teeth in these sets are offset longitudinally from the teeth of adjacent sets so that the teeth cannot track as the cutter rolls against the earth formation at the bottom of the well.

Another object of this invention is to provide a roller cutter in which the teeth are related in such a manner that they have a very desirable chipping action and yet have a minimum of longitudinal cutting edge in engagement with the bottom of the well at any one time, so that the feed pressures are concentrated on the edges to assure a rapid cutting action.

Another object of this invention is to provide a roller cutter of the character mentioned that is capable of wide variation to adapt it for practically any use or application.

The various objects and features of myinvention will be fully understood from the following detailed description of typical preferred forms `and applications of my invention, throughout which description reference is made to the accompanying drawing, in which:

Fig. 1 is an end View of one form of cutter of the invention. Fig. 2 is a side view of the cutter illustrated in Fig. 1. Fig. 3 is an end View of another form of the cutter and Fig. 4 is a side elevation of the cutter illustrated in Fig. 3.

The form of the invention illustrated in Figs. 1 and 2 may be said to comprise, generally, a cutter body lil and a plurality of teeth II on the body I0 arranged in series of longitudinal rows X, Y and Z with the teeth of the adjacent series longitudinally offset,

The body I0 of course may be varied in size and proportions to adapt the cutter for the intended use. The cutter body I0 is a frusto-conical member provided with a central longitudinal opening I2 to facilitate its rotatable mounting on the bit body. The opposite ends of the body I0 may be nat and at right angles to the longitudinal aXis of the cutter. The cutter is formed from a frusto-conical body or blank and the teeth Il are formed by making grooves and cuts in this blank, The groups or series X, Y and Z of the longitudinal rows of teeth II are circumferentially distributed around the body I0 and the teeth II of correspondingly designated series are of the same shape and longitudinal disposition. There may be as many teeth II as required and as many longitudinal rows of teeth as found most desirable. In the construction illustrated there are iifteen longitudinal rows of teeth II, there being two series X, two series Y and one series Z with three longitudinal rows of teeth II in each of these series. In constructing the teeth II a plurality of equally spaced longitudinal cuts or grooves I3 are made in the blank or cutter body I0. The grooves I3 are of like size, shape and circumferential spacing and extend throughout the length of the body I0. In accordance with the invention the grooves I3 are pitched or angularly related to radial longitudinal planes of the body I0 and have the same or equal pitch. The degree of pitch or angularity of the grooves I3 may be varied but it is preferred to form the grooves at substantially the pitch illustrated in Fig. 2for the reason to be hereinafter described. rIhe side walls of the longitudinal grooves I3 are flat and inwardly convergent. In the form of the invention illustrated in Figs. 1 and 2 of the drawingthe grooves I3 are spaced and proportioned so that the side walls of adjacent grooves I3 join to provide the teeth II with longitudinally extending cutting edges I4.

The individual teeth of the longitudinally extending groups or series X, Y and Z are formed or defined by circumferentially extending serrations or grooves I5. The grooves I5 are straight and normal, that is, they lie in planes at right angles to the longitudinal axis of the cutter body Il) as distinguished from the helical serrations or l grooves found in most cutters. The grooves I5 cross or interrupt the longitudinal grooves I3 and their side walls form the upper and lower ends of the teeth It is a feature of the invention that the grooves I5 defining the teeth II of one series X, Y or Z are longitudinally offset from the serrations separating or defining the teeth of an adjacent series so that the teeth of the adjacent series X, Y and Z throughout the circumference of the cutter are longitudinally offset. In making the grooves I5 a series of cuts or grooves of equal size and spacing are formed to pass through three adjacent longitudinal ridges as left by the longitudinal grooves I3. The cut is then offset longitudinally a distance equal to one third of the spacing of the individual grooves and the three adjacent longitudinal ridges are then cut and so on. Thus the grooves I5 defining or separating the teeth I I in a group or series X may be rst formed and the grooves I5 defining or separating the teeth |I in the adjacent series Z may then be formed in an offset relation to the first grooves a distance equal to one third the spacing of the individual grooves and a set of grooves I5 may then be formed in the adjacent series Y with the last named grooves longitudinally offset a distance equal to one third the spacing of the individual grooves. It is preferred to form each set of grooves I5 in a number of longitudinal rows of teeth which will if;

evenly divide into the total number of longitudinal rows of teeth II. Thus, where there are fifteen longitudinal rows of teeth II each set of grooves I5 may intersect three adjacent longitudinal grooves I3 to define the teeth II in a series X, Y or Z. By reason. of the longitudinal offsetting of the grooves I5 described above the teeth I I in one series Y or Z are in the sainer circumferential planes as the teeth in the other correspondingly designated series X, Y or Z.

The above mentioned pitch of the longitudinal grooves I3 is preferably such that the cutting edges I4 of the teeth of adjacent longitudinal rows of teeth in any one series X, Y or Z, and at the opposite ends of the cutter lie in substantially the same longitudinal or radial plane. This pitching of the longitudinal grooves I3 assures the necessary chipping action of the teeth with a most effective distribution of the feed pressures throughout the length of the cutter. It will be observed that the longitudinal offsetting of the transverse grooves I5 occurring in the adjacent series X, Y and Z may leave or form teeth at the ends of the body II! that are excessively narrow. These excessively narrow end teeth may be cut off or broken ofi as desired. Further, due to the straight angular pitch of the longitudinal grooves I3 formed in the substantially true conical body IIJ, the cutting edges I4 of the teeth II at the ends of the longitudinal rows may be somewhat thicker than the edges of the intermediate teeth. This inequality in the thickness of the cutting edges I4 may be compensated for by making the cutter blank or body Ill of khyperboloid shane to follow or generallyrcorrespond Cil to the form of the bases of the longitudinal grooves I3 or, if desired, the grooves I3 may be formed in a substantially true conical body I0 and the narrow cutting edges I5 of the intermediate teeth may be built up following the cutting operation, so that the several cutting edges are of substantially uniform thickness. While I have illustrated and described the grooves I3 as straight inclined grooves, it is to be understood that they may be helically pitched, if desired.

In the use or operation of the cutter illustrated in Figs. 1 and 2 the cutter body I0 is rotatably supported on the bit or well tool so that it may rotate about its own axis through contact with the earth formation. As the bit or well tool is rotated in the well the teeth II of the cutter act on and out away the earth formation. As the cutter body I rotates the series X, Y and Z of the teeth successively come into cutting engagement with the earth formation. The teeth I in the successive series X, Y and Z are longitudinally staggered and, therefore, cannot track in their action on the earth formation. The teeth II arranged in the pitched longitudinal rows cannot simultaneously cooperate with the earth formation throughout the length of any given row and the feed pressures are, therefore, concentrated on the cutting edges I4 as the teeth successively come into contact with the earth formation. However, the teeth |I are arranged in rows which extend approximately longitudinally of the cutter body I0 so that the cutting edges I4 of the teeth have an eiiicient chipping action. The serrations or grooves l5 defining the ends of the teeth are straight and lie in planes normal to the axis of rotation of the cutter so that jets -of circulation fluid directed at right angles to said axis may fully flush out the grooves to prevent balling up of the cutter The form of cutter illustrated in Figs. 3 and 4 comprises, generally, a cutter body lila and cutting teeth ||a projecting from the body |33.

The body I0SL may be of the same shape as the body I0. The teeth IIa diier from the teeth I I in that their cutting edges I4il extend circumferentially of the body |02. The teeth IIa are arranged in longitudinal rows which are pitched relative to the longitudinal axis of the body I!!a and said vrows of teeth ||EL occur in series, with the teeth in the adjacent series offset longitudinally of the body.

The teeth I Ia are formed by making a plurality of like uniformly spaced longitudinal grooves I3a and sets of transverse or circumferential serrations or grooves |5a intersecting the grooves |35.

The grooves I5et are spaced and proportioned to provide the teeth IIa with the circumferentially extending cutting edges, Illa, that is, the side walls of adjacent grooves I5a converge to. define the cutting edges I4a. In accordance with the invention the grooves I5a are straight and lie in planes normal to the longitudinal axis of the cutter body |03. The transverse grooves I5a are made in sets or groups with the grooves of each group intersecting a number of longitudinal grooves |33. The grooves I5a of one group are offset longitudinally from the grooves I5a of the adjacent groups so that the longitudinal grooves I3a and the circumferential grooves I5a form or define series X, Y and Z of longitudinal rows of teeth with the teeth IIVa in adjacent series longitudinally offset. In this respect the teeth I la are related in the same manner as the teeth described above. The longitudinal grooves I3a forming the ends or longitudinal limits of the teeth I Ia may be straight as illustrated, or if desired may be helically pitched.

The cutter shown in Figs. 3 and 4 operates in substantially the same manner as the cutter shown in Figs. 1 and 2 except that the cutting edges its of the teeth Ila have a slightly different engagement with the earth formation. The teeth Ila in the adjacent series X, Y and Z are longitudinally offset and the cutting edges Ma of the adjacent groups of teeth cannot track in their engagement with the earth formation. The straight circumferential serrations or grooves I5a assure the full flushing of the cutter by jets directed at right angles to the cutter.

Having described only typical preferred forms and applications of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may ap-pear to those skilled in the art, or fall within the scope of the following claims:

Having described my invention, I claim:

1. A roller cutter comprising a body, longitudinally extending circumferentially spaced rows of teeth on said body extending around the entire periphery thereof, said rows of teeth being pitched relative to the longitudinal axis of the body, the individual teeth being separated by intersecting grooves, some of which extend longitudinally of and others of which extend circumferentially of the body and lie in planes substantially normal to the longitudinal axis of the body, cutting edges on the teeth which extend circumferentially of the body, said rows occurring in contiguous groups each of which includes several of said rows, the corresponding teeth in each group occupying like positions in the several rows and occupying like positions on the body, the correspondingly positioned teeth in the contiguous groups being progressively offset longitudinally of the body in the same direction so that the cutting edges of the teeth in the dierent groups do not track in their engagement with the earth formation.

2. A roller cutter comprising a body, longitudinally extending circumferentially spaced rows of teeth on said body extending around the entire periphery thereof, said rows of teeth being pitched relative to the longitudinal axis of the body, the individual teeth being separated by intersecting grooves, some of which extend longitudinally of and others of which extend circumferentially of the body and lie in planes substantially normal to the longitudinal axis of the body, cutting edges on the teeth which extend circumferentially of the body, said rows occurring in contiguous groups each of which includes several of said rows, the corresponding teeth in each group occupying like positions in the several rows and occupying like positions on the body, the

correspondingly positioned teeth in the contigu? ous groups being progressively offset longitudinally of the body in the same direction so that the cutting edges of the teeth in the different groups do not track in their engagement with the earth formation, said rows being pitched relative to radial planes of the body so that the cutting edge of a tooth at one end of the body lies in substantially the same radial plane of the body as the cutting edge of a tooth at the other endV of the body occurring in an adjacent row in the same group.

ALFRED C. CATLAND. 

